NYC Renovation Chronicles: The sound and the fury

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Noise-wise, most
New Yorkers have learned to tolerate trash trucks, sirens and the sermons of
subway preachers, but in the sanctity of one’s apartment, the sound of a
neighbor’s muffled conversation can be as disruptive as a root canal.

Worse, perhaps,
is the golden rule of sound transmission: If you can hear your neighbor in
their space, they can hear you in yours.

There are
several things you can do during a gut renovation to sound-proof your home;
even if you’re not renovating, there are some simple procedures that can help.
To determine the right solution for your circumstances, you must first identify
the type of noise causing the problem.

Acoustics 101

Sound is
transmitted through vibrations in any medium. With regard to urban residential
spaces, we are typically concerned (1) with sound that is transmitted through
the air, a.k.a. airborne sound, and (2) sound that travels through the building
structure, a.k.a. structure-borne sound.

The sound of someone
arguing next door or the sound of loud traffic are examples of airborne sound
transmission problems. Structure-borne sound is also known as impact noise. The
sound of a tennis ball bouncing, or footsteps above you would be examples of
structure borne sound transmission problems. These problems often occur
together, as when you hear both the loud sound and the rumbling of a demolition
crew chopping concrete.

A third type of
noise problem is sound reflection,
which occurs when the sound from within a space bounces around and creates
internal noise. Examples of sound reflection problems would be reverberation
(where sound reflects off hard surfaces after its source has stopped) or
resonance (such as the buzzing sound of materials vibrating in response to loud
sound).

Each of these
problem types is handled with a different solution.

1. Airborne noise solutions

If your
neighbor’s lively nocturnal discussions are keeping you awake, you might
consider installing an additional layer or two of gypsum board over your shared
wall or ceiling. If that doesn’t
help, you can try a heavier material such as cement board or sheet lead. The
additional mass will prevent the sound from leaking through the walls.

Just keep in
mind that any sound-proofing is only as strong as its weakest link. If you
cover your wall, holes around electrical outlets need to be filled with
acoustic sealant as should any space at the baseboard. The same is true for the
ceiling where, no matter how many layers of gypsum board you employ, recessed
lights will serve as megaphones if left uninsulated.

I was told once
that the floors of The Dakota were filled with sand. Whether or not true, I
don’t know, but given its weight and ability to absorb vibration, sand does
wonders as sound-proofing. I just wouldn’t try this at home as your building
structure probably wouldn’t be able to support the weight – and your downstairs
neighbor might not appreciate the retrofit.

2. Structure borne noise solutions

Structure borne
noise, such as that of someone jumping or moving
furniture, travels through all components of the building that are rigidly
connected. Noise of this type is best addressed by physically isolating
adjacent spaces from one another on springs or some other elastic component to
disrupt sound from bridging between spaces. This is referred to as
discontinuous construction.

Carpet, the simplest
solution of this type, is normally required by your board over 80 percent of
your floor area for this very reason. Other effective solutions require a lot
more than a trip to ABC Carpet.

To
sound isolate a ceiling, for example, the finished gypsum board surface is
suspended from the slab and beams above either on rubberized pads or more
effectively, on springs. In
both cases, the ceiling should not be tied rigidly to the side walls or it will
defeat the purpose of isolating it. Similarly, the interior walls should not be
rigidly tied to the structure—it should be isolated on elastic strips if
possible. In extreme cases, where space is not an issue (hah!), you can build a
completely independent wall separate from the apartment’s perimeter wall.

Seeking new
office space recently, I checked out a space with spectacular views – next to a
drummer’s studio. The place wasn’t right for me, but not because of the
acoustics. The drummer had sound isolated his studio by creating secondary
interior walls that were extraordinarily effective at keeping the melodic
banging inside his space.

3. Sound reflection noise solutions

Anyone who has
dined in a restaurant devoid of soft surfaces understands the frustration of
sound reflection noise. An abundance of hard surfaces can be problematic,
particularly where clarity of sound is important, such as in a home theater, or
in a room used for entertaining. Solutions in such circumstances involve the
addition of soft materials such as carpet, drapery, or upholstery.

There are
also sound absorption panels made specifically for this purpose, as well as a
spray on acoustic plaster. (Note: The latter leaves a rough
texture a lot of people don’t like so you might want to run it by your
decorator before committing.)

Other helpful hints...

Single pane
windows are not only terrible heat insulators, they also do little to prevent
sound infiltration. A double pane window will do wonders to achieve greater
sound privacy. Short of a full-blown window replacement, some companies make
interior windows that can be installed in front of yours at the interior to
similar effect.

For doors, the
heavier the better. A hollow core door is little better than an open window in
terms of soundproofing. Likewise, installing rubber gaskets around the
doorframe will prevent sound from seeping through the edges. And if sound is a
big issue for you, stay away from sliding doors. It is impossible to insulate
them.

Lastly, it is
important to isolate any machinery that vibrates. Washers and dryers should be
placed on rubber blocks. And mechanical equipment should be hung from the
structure on isolation springs.

At the end of the day, though, it comes down
to what you can live with – or what you can afford to change. Some people can
tolerate a lot more noise than others, and if you find yourself searching for
silence in this city, you're probably in the wrong place.

David Katz(www.KATZarch.com) has been practicing architecture in New York City for the last 20 years. Detail oriented, nervous and a little neurotic, he specializes in co-op and condo renovations.

Disclaimer: Information provided herein is not to be construed as professional advice. Readers are urged to consult with a licensed architect regarding their specific circumstances prior to undertaking any renovation work. (We do not want any buildings falling down!)

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